Polyhedral oxaplatinaborane chemistry: characterisation of [9,9-(PMe 2Ph) 2- arachno-9,6-PtOB 8H 10] and its metallaborane non-oxa cognate [6,6-(PMe 2Ph) 2- arachno-6-PtB 9H 11-9-(PMe 2Ph)

Abstract

Reaction of [(PMe 2Ph) 2PtB 8H 12] with KH and [{( η 5-C 5Me 5)RhCl 2} 2] followed by chromatographic separation in air unexpectedly gave the ten-vertex oxametallaborane [9,9-(PMe 2Ph) 2- arachno-9,6-PtOB 8H 10] ( 1, 11%), which has a classical arachno ten-vertex geometry with the {O} and{Pt(PMe 2Ph) 2} vertices in the prow (6)- and (9)-positions; the oxygen atom is therefore bound contiguously to boron atoms only. Reaction of [PtMe 2(PMe 2Ph) 2] with [6,9-(PMe 2Ph) 2B 10H 12] generates its ten-vertex metallaborane cognate [6,6-(PMe 2Ph) 2- arachno-6-PtB 9H 11-9-(PMe 2Ph)] ( 3, 10%), and completes a coherent B→C→N→O cluster constituent sequence. Compounds 1 and 3 are characterised by single-crystal X-ray diffraction analysis and NMR spectroscopy.